Below is a video of how I made the 5/16" plugs. The plugs that are commercially available are solid wood, and the grain goes in the wrong direction (top and bottom of plug is end grain). While this orientation will accept glue better, I did not want it for the drum in case of expansion/contraction. I am afraid that it would show as a depression under the wrap over time. This fear may be unfounded, but who knows...
Additionally, commercial plugs are tapered quite a bit. They are not designed to fully fill a plywood void - their purpose is simply to hide a fastener (screw, typically) from view.
As I describe in the video, I couldn't find a plug cutter in 5/16" size, so I had to make the plugs larger and sand them down. To use the plug cutter, you must use a drill press. The odds are against you successfully cutting them with a handheld drill. I came up with the method described in the video by determining that it is really no big deal to have to fill the 1/32" center hole with wood putty and sand it smooth.
Once I have cut the plugs in the plywood donor board, I pried them free with a small, flat-bladed screwdriver. Some of them needed a little sanding to level the bottom. I made far more than I needed, because something always goes wrong, and it's nice to have spares.
I sized the holes in the plugs slightly larger than the diameter of the brad so that they would spin freely, but not so loosely that the finished product was out of round.
More soon...
Josh
[ame]https://youtu.be/D9OpW5X0beQ[/ame]